Seedlings - Lights, Camera, Problem!

I inherited a light fixture for my seedlings and I am thrilled about it.  My husband is equally thrilled because we now have our dining room table back.  However, my seedlings were not so thrilled about their new environment.

We moved the seed trays to the basement last Saturday so the light fixture could hang from a joist easily, as the basement is unfinished.

By Monday morning, I noticed a change in the happiness level of some of my babies. They were feeling little blue (well, purple) from losing their old home.  They were pouting (not growing), too.  Most of the tomato plants and all of the marigolds now had purple coloring on their leaves. The underside leaves and stems of the 'maters were now a not-so lovely shade of violet.

As for the marigolds, the tops of the marigold leaves were now tinged purple.

I've never experienced this deep, dark, purple issue and I was worried.  All this hard work down the drain??  No!  After researching quite a bit online and at my local organic gardening and hydroponics store, I've come to the conclusion that my poor baby plants suffered from a phosphorus deficiency due to cold soil.  As you know, I've been feeding them at every watering with Smart Tea so I doubted it was a lack of nutrients.  I learned that if the soil temps fall (as my chilly 55* basement provides), the phosphorus is unavailable to the delicate root system.

I purchased two seedling heat mats (one that fits 4 trays and one that fits 2 trays) for about $130.

On Saturday, one week after moving them to the basement, we padded the floor with some foam puzzle pieces and hooked the seed mats up.  The heating mats raise the soil temperature to 10-20* above the ambient temp.  And they're waterproof so you can go ahead and quench your babies' thirst without fearing electrocution.

It's currently about 28 hours later and I think (or is it just my hopeful wishing?!) that the purple tint has lessened.  I will continue to monitor this situation closely and report back.

Could it be something else?  Sun-scorch?  If you have experienced this problem, I'd love to hear from you.


Katie McGarry said...

Very interesting. I've never knew this was a problem or that they sold heating pads for plants. Who knew?

Chad said...

Yes, the culprit is most likely the cold concrete in the basement preventing the soil from warming. Seedlings need a nice, warm bed. At such an early stage of growth, nutrient deficiency should not yet be a problem. Just my 2c.

ArtBusinessMentor.com said...

Also, you might want to use a florescent light (not sodium vapor) for seedlings - especially so early in the game. It has to do more with the seedlings needing more of the blue light spectrum (florescent) and not so much the yellow-red spectrum that sodium vapor gives off. Once they get about 6" inches and your about two weeks from moving them outside, then you roll over to the sodium vapor light. At that point stand back - they'll take off!